#ifndef DEMO12_H
#define DEMO12_H
#include "demo11.h"
class demo12_disc : public demo11_basic
{
public:
    demo12_disc() = default;
    demo12_disc(const string &book, double price, size_t qty, double disc) : demo11_basic(book, price), quantity(qty), discount(disc) {}
    double net_price(size_t n) const = 0;

protected:
    size_t quantity = 0;
    double discount = 0.0;
};

#endif // !